从技术上讲，这是正确的——只有'eval'不会派生另一个shell。然而，从您试图在修改后的环境中运行的应用程序的角度来看，差异为零:子进程继承其父进程的环境，因此(修改后的)环境被传递给所有下行进程。

事实上，只要你在父程序/shell下运行，更改的环境变量就会“保持不变”。

If it is absolutely necessary for the environment variable to remain after the parent (Perl or shell) has exited, it is necessary for the parent shell to do the heavy lifting. One method I've seen in the documentation is for the current script to spawn an executable file with the necessary 'export' language, and then trick the parent shell into executing it -- always being cognizant of the fact that you need to preface the command with 'source' if you're trying to leave a non-volatile version of the modified environment behind. A Kluge at best.

The second method is to modify the script that initiates the shell environment (.bashrc or whatever) to contain the modified parameter. This can be dangerous -- if you hose up the initialization script it may make your shell unavailable the next time it tries to launch. There are plenty of tools for modifying the current shell; by affixing the necessary tweaks to the 'launcher' you effectively push those changes forward as well. Generally not a good idea; if you only need the environment changes for a particular application suite, you'll have to go back and return the shell launch script to its pristine state (using vi or whatever) afterwards.

简而言之，没有好的(简单的)方法。想必这很难确保系统的安全性不会受到不可挽回的损害。

从技术上讲，这是正确的——只有'eval'不会派生另一个shell。然而，从您试图在修改后的环境中运行的应用程序的角度来看，差异为零:子进程继承其父进程的环境，因此(修改后的)环境被传递给所有下行进程。

事实上，只要你在父程序/shell下运行，更改的环境变量就会“保持不变”。

If it is absolutely necessary for the environment variable to remain after the parent (Perl or shell) has exited, it is necessary for the parent shell to do the heavy lifting. One method I've seen in the documentation is for the current script to spawn an executable file with the necessary 'export' language, and then trick the parent shell into executing it -- always being cognizant of the fact that you need to preface the command with 'source' if you're trying to leave a non-volatile version of the modified environment behind. A Kluge at best.

The second method is to modify the script that initiates the shell environment (.bashrc or whatever) to contain the modified parameter. This can be dangerous -- if you hose up the initialization script it may make your shell unavailable the next time it tries to launch. There are plenty of tools for modifying the current shell; by affixing the necessary tweaks to the 'launcher' you effectively push those changes forward as well. Generally not a good idea; if you only need the environment changes for a particular application suite, you'll have to go back and return the shell launch script to its pristine state (using vi or whatever) afterwards.

简而言之，没有好的(简单的)方法。想必这很难确保系统的安全性不会受到不可挽回的损害。

我很多年前就这么做了。如果我没记错的话，我在.bashrc和.cshrc中都包含了一个别名，并带了参数，以别名形式将环境设置为公共形式。

然后，您将在这两个shell中的任何一个中获取的脚本都具有带有最后一种形式的命令，该命令适用于在每个shell中使用别名。

如果我找到具体的化名，我会公布的。

在OS X bash下，您可以执行以下操作: 创建bash脚本文件以取消该变量的设置

#!/bin/bash
unset http_proxy

使文件可执行

sudo chmod 744 unsetvar

创建别名

alias unsetvar='source /your/path/to/the/script/unsetvar'

只要将包含脚本文件的文件夹添加到路径中，它就可以使用了。

在我的.bash_profile我有:

# No Proxy
function noproxy
{
    /usr/local/sbin/noproxy  #turn off proxy server
    unset http_proxy HTTP_PROXY https_proxy HTTPs_PROXY
}


# Proxy
function setproxy
{
    sh /usr/local/sbin/proxyon  #turn on proxy server 
    http_proxy=http://127.0.0.1:8118/
    HTTP_PROXY=$http_proxy
    https_proxy=$http_proxy
    HTTPS_PROXY=$https_proxy
    export http_proxy https_proxy HTTP_PROXY HTTPS_PROXY
}

当我想禁用代理时， 函数在登录shell中运行并设置变量 正如预期和希望的那样。

这不是我所说的杰出的，但如果您需要从shell调用脚本，这也可以工作。这不是一个很好的解决方案，但对于一个单一的静态环境变量，它工作得足够好了。

1)。创建一个条件为0(成功)或1(不成功)的脚本

if [[ $foo == "True" ]]; then
    exit 0
else
    exit 1

2)。创建依赖于退出代码的别名。

alias='myscript.sh && export MyVariable'

调用别名，别名调用脚本，脚本计算条件，条件必须通过'&&'退出0，以便在父shell中设置环境变量。

这是垃圾，但在紧要关头可以派上用场。